Light emitting device

ABSTRACT

This disclosure discloses a light-emitting chip comprises: a light-emitting stack, having a side wall, comprising an active layer emitting light; and a light-absorbing layer having a first portion surrounding the side wall and being configured to absorb 50% light toward the light-absorbing layer.

REFERENCE TO RELATED APPLICATION

This application claims the right of priority based on U.S. provisionalapplication Ser. No. 61/802,792, filed on Mar. 18, 2013, and the rightof priority based on TW application Serial No. 102127373, filed on Jul.30, 2013. The entire contents of each of these applications are herebyincorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a light-emitting device, and inparticular to a light-emitting device comprising a light-absorbinglayer.

2. Description of the Related Art

The light-emitting diodes (LEDs) of the solid-state lighting elementshave the characteristics of low power consumption, low heat generation,long operational life, shockproof, small volume, quick response and goodopto-electrical property like light emission with a stable wavelength sothe LEDs have been widely used in household appliances, indicator lightof instruments, and opto-electrical products, etc.

A light-emitting diode usually comprises a light-emitting stack and twoelectrodes provided for injecting a current into the light-emittingstack for emit light. In general, two electrodes are design to have acurrent spreading throughout the light-emitting stack such that alight-emitting area configured to emit light is substantially the sameas the surface area of the light-emitting stack. However, in otherapplication, there is a need for a light-emitting having a limitedlight-emitting area with a high current density for improving lightefficiency thereat.

SUMMARY OF THE DISCLOSURE

The present disclosure provides a light-emitting device.

This light-emitting device comprises: a light-emitting stack, having aside wall, comprising an active layer emitting light; and alight-absorbing layer having a first portion surrounding the side walland being configured to absorb 50% light toward the light-absorbinglayer.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing is included to provide easy understanding ofthe application, and is incorporated herein and constitutes a part ofthis specification. The drawing illustrates the embodiment of theapplication and, together with the description, serves to illustrate theprinciples of the application.

FIG. 1 shows a top view of a light-emitting device in accordance withthe first embodiment of the present disclosure.

FIG. 2 shows a cross-sectional view of the light-emitting device, takenalong line AA′ of FIG. 1.

FIG. 3 shows a top view of a light-emitting device in accordance withthe second embodiment of the present disclosure.

FIG. 4 shows a cross-sectional view of the light-emitting device, takenalong line BB′ of FIG. 3.

FIG. 5A shows a top view of a light-emitting device in accordance withthe third embodiment of the present disclosure.

FIG. 5B shows a cross-sectional view of the light-emitting device, takenalong line XX′ of FIG. 5A.

FIG. 6 shows a top view of a light-emitting device in accordance withthe third embodiment of the present disclosure.

FIG. 7 shows a top view of a light-emitting device in accordance withthe third embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To better and concisely explain the disclosure, the same name or thesame reference number given or appeared in different paragraphs orfigures along the specification should has the same or equivalentmeanings while it is once defined anywhere of the disclosure.

The following shows the description of embodiments of the presentdisclosure in accordance with the drawing.

FIGS. 1 and 2 disclose a light-emitting device 100 in accordance withthe first embodiment of the present disclosure. FIG. 1 shows the topview of the light-emitting device 100 and FIG. 2 shows thecross-sectional view of the light-emitting device 100. Thelight-emitting device 100 comprises a substrate 10, a light-emittingstack 13 formed on the substrate 10, a reflective layer 12 formedbetween the substrate 10 and the light-emitting stack 13, and a bondinglayer 11 formed between the reflective layer 12 and the substrate 10.The light-emitting stack 13 comprises a first-type conductivitysemiconductor layer 131, a second-type conductivity semiconductor layer133, and an active layer 132 sandwiched between the first-type andsecond-type conductivity semiconductor layers 131, 133. The first-typeand second-type conductivity semiconductor layers 131, 133 respectivelyprovide electrons and holes such that electrons and holes can becombined in the active layer 132 to emit light when a current is appliedthereto. The material of the light-emitting stack 13 comprises III-Vgroup semiconductor material, such as Al_(x)In_(y)Ga_((1-x-y))N orAl_(x)In_(y)Ga_((1-x-y))P, wherein 0≦x, y≦1; (x+y)≦1. Depending on thematerial of the active layer 132, the light-emitting stack 13 is capableof emitting a red light with a wavelength in a range from 610 nm to 650nm, a green light with a wavelength in a range from 530 nm to 570 nm, ablue light with a wavelength in a range from 450 nm to 490 nm or a UVlight with a wavelength in a range from 400 nm-450 nm. A method ofmaking the light-emitting stack 13 is not limited to but comprisesMetal-organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy(MBE), Hydride Vapour Phase Epitaxy (HVPE), evaporation or ionelectroplating. The light-emitting device 100 further comprises a firstelectrode 16 formed on the second-type conductivity semiconductor layer133, a second electrode 17 formed on the substrate 10, a light-absorbinglayer 18 formed on a portion of the first electrode 16, and aninsulation layer 19 formed between the light-absorbing layer 18 and thesecond-type conductivity semiconductor layer 133. In this embodiment,the first electrode 16 is patterned and comprises an inner segment 161,an outer segment 162, and a plurality of extending segments 163electrically connected the inner segment 161 with the outer segment 162.As shown in FIG. 2, the light-emitting device 100 further comprises anohmic contact layer 15 formed between the inner segment 161 and thelight-emitting stack 13 for providing an ohmic contact paththerebetween. The ohmic contact layer 15 has a shape substantially equalto that of the inner segment 161. The ohmic contact layer 15 is notformed between the outer segment 162 and the light-emitting stack 13.Alternatively, the ohmic contact layer 15 can be formed between theouter segment 162 and the light-emitting stack 13, and has a shapesubstantially equal to that of the outer segment 162 (not shown). Theinner segment 161 and the outer segment 162 comprise a circle,rectangle, quadrangle or polygon in shape. When the inner segment 161and the outer segment 162 are a circle in shape, they are concentric.

Referring to FIG. 2, the second-type conductivity semiconductor layer133 of the light-emitting stack 13 has a side wall 1331 and a topsurface. The top surface has a first region 1332 and a second region1333. The second portion 1333 is defined by the outer segment 162 formedon the first region 1332 such that the first region 1332 surrounds thesecond region 1333. Specifically, the outer segment of the first region1332 surrounds the second region 1333. The inner segment 161 is formedon a portion of the second region 1333 without covering the entiresecond region 1333 so a partial second-type conductivity semiconductorlayer 133 is exposed for the light emitted from the active layer 132 topass outside the light-emitting device 100 therethrough. The exposedsecond region 1333 where there is no inner segment 161 disposed can beroughed by etching such as dry etching or wetting etching for improvinglight extraction. The light-absorbing layer 18 has a first portion 181surrounding the side wall 1331 and a second portion 182 above the firstregion 1332 of the top surface of the light-emitting stack 13.Specifically, the insulation layer 19 and the outer segment 162 isformed on and covering the first region 1332 of the top surface of thesecond-type conductivity semiconductor layer 133 and the second portion182 of the light-absorbing layer 18 is formed on and covering theinsulation layer 19 and the outer segment 162. In addition, theinsulation layer 19 covers the side wall 1331 of the light-emittingstack 13 and the first portion 181 covers a side wall of the insulationlayer 19. Since the ohmic contact layer 15 is merely formed between theinner segment 161 and the light-emitting stack 13, the active layer 132below the inner segment 161 (that is, the second region) emits lightsuch that a first quantity of the light (more than 90%) directly passesoutside the light-emitting device 100 through the second region 1333 anda second quantity of the light (less than 10%) may emit toward thelight-absorbing layer 18 which is configured to absorb light. In oneembodiment, more than 50% of the second quantity of the light isabsorbed by the light-absorbing layer 18. In addition, the light emittedfrom the active layer 132 does not pass outside the light-emittingdevice 100 through the first region 1332 and the side wall 1331. A ratioof an area of the second portion 1333 to an area of the top surface ofthe light-emitting stack 13 is between 10%-90%, that is, alight-emitting area is defined as 10%-90% of the area of thelight-emitting stack 13. The light-absorbing layer 18 can comprise asingle layer or a plurality of sublayers and has a thickness larger than300 Å. The light-absorbing layer 18 comprises titanium (Ti), chromium(Cr), nickel (Ni), or combinations thereof. The first electrode 16comprises metal or metal alloy. The metal comprises Cu, Al, Au, La, orAg. The metal alloy comprises La, Ge—Au, Be—Au, Cr—Au, Ag—Ti, Cu—Sn,Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, or Ni—Co. The light-absorbinglayer 18 can comprise a bonding pad for wire bonding to an externalstructure (not shown), for example, a submount, and therefore forming anelectrical connection therebetween when in operation.

In this embodiment, the reflective layer 12 is embedded within thebonding layer 11 in a position corresponding to the second portion 1333of the top surface of the light-emitting stack 13. Accordingly, when thelight emitted from the active layer 132 emits toward the substrate 10,the light can be reflected by the reflective layer in opposite directiontoward the second-type conductivity semiconductor layer 133. Since someof the light only passes outside through the second portion 1333 of thetop surface of the second-type conductivity semiconductor layer 133, thereflective layer 12 has an area substantially equal to that of thesecond portion 1333 of the top surface of the light-emitting stack 13.In other embodiment, the reflective layer 12 can have an areasubstantially larger than that of the second portion 1333 of the topsurface of the light-emitting stack 13.

FIGS. 3 and 4 disclose a light-emitting device 200 in accordance withthe second embodiment of the present disclosure. FIG. 3 shows the topview of the light-emitting device 200 and FIG. 4 shows thecross-sectional view of the light-emitting device 200. Thelight-emitting device 200 has the similar structure with the firstembodiment of the light-emitting device 100 except that the innersegment 161 has two inner sub-segments 1611, 1612. A plurality of firstextending segment 1631 electrically connects the two inner sub-segments1611, 1612 with the outer segment 162 and a plurality of secondextending segments 1632 electrically connects one of the two innersub-segments 1611, 1612 with the outer segment 162. The first extendingsegment 1631 and the second extending segments 1632 are alternatelyarranged. The outer segment 162 comprises a plurality of protrusions164. The outer segment 162 and the protrusions 164 are provided fordefining the second region 1333 where the light emitted from the activelayer 132 merely passes outside the light-emitting device 200therethrough. As shown in FIG. 4, the ohmic contact layer 15 is formedbetween the two inner sub-segments 1611, 1612 and the light-emittingstack 13 for providing an ohmic contact path therebetween. The ohmiccontact layer 15 has a shape substantially same as that of the two innersub-segments 1611, 1612 of the inner segment 161. The ohmic contactlayer 15 is not formed between the outer segment 162 and thelight-emitting stack 13. Alternatively, the ohmic contact layer 15 canbe formed between the outer segment 162 and the light-emitting stack 13,and has a shape substantially same as that of the outer segment 162. Theinner two sub-segments 1611, 1612 of the inner segment 161 and the outersegment 162 comprise a circle, rectangle, quadrangle or polygon inshape. When the two inner sub-segments 1611, 1612 of the inner segment161 and the outer segment 162 are a circle in shape, they areconcentric. A ratio of an area of the second portion 1333 to an area ofthe top surface of the light-emitting stack 13 is between 10%-90%. It isnoted that numbers of the inner segment and the outer segments can bevaried depending on the actual requirements. The larger the desired areaof the second region where the light emitted from the active layerpasses outside the light-emitting device therethrough, the more numbersof the inner segment and the outer segments are.

FIGS. 5A and 5B disclose a light-emitting device 300 in accordance withthe third embodiment of the present disclosure. FIG. 5A is a top view ofthe third embodiment. FIG. 5A shows a cross-sectional view of thelight-emitting device, taken along line XX′ of FIG. 5A. As shown in FIG.5A, the light-emitting device 300 comprises a light-emitting area and anelectrode area surrounding the light-emitting area. The light-emittingarea is substantially arranged in a center of the light-emitting device300. The electrode area is a light-absorbing area, or anon-light-emitting area. The light-emitting area has a shape of circlein top view. It is noted that the shape is not limited and can bepolygon, such as triangle or square. Assuming the shape of thelight-emitting area is a circle, its diameter is between 0.004-0.5 mm.In one embodiment, the diameter is between 0.001-0.2 mm. Thelight-emitting device 300 has a structure similar to the light-emittingdevice 100 of the first embodiment, except that the light-emittingdevice 300 comprises a trench 20 for separating an epitaxial structure33 into a first semiconductor structure 22 and a second semiconductorstructure 24. The first semiconductor structure 22 has a shape of circlein top view and the second semiconductor structure 24 surrounds thefirst semiconductor structure 22. The first semiconductor structure 22and the second semiconductor structure 24 have substantially the sameepitaxial structure 33 and have the same material composition and thesame stacking structure. The epitaxial structure 33 comprises afirst-type conductivity semiconductor layer 331, a second-typeconductivity semiconductor layer 333, and an active layer 332 disposedbetween the first-type conductivity semiconductor layer 331 and asecond-type conductivity semiconductor layer 333. The trench 20separates the active layer 332 and the second-type conductivitysemiconductor layer 333 of the first semiconductor structure 22 from theactive layer 332 and the second-type conductivity semiconductor layer333 of the second semiconductor structure 24. However, the first-typeconductivity semiconductor layer 331 of the first semiconductorstructure 22 and the first-type conductivity semiconductor layer 331 ofthe second semiconductor structure 24 are physically connected with eachother. When the first semiconductor structure 22 is driven by a current,the active layer 332 of the first semiconductor structure 22 can emit afirst light with a first main wavelength; and when the secondsemiconductor structure 24 is driven by a current, the active layer 332of the second semiconductor structure 24 can emit a second light with asecond main wavelength. The first main wavelength and the second mainwavelength are within the same wavelength range. The first mainwavelength and the second main wavelength have the same wavelength, forexample, a red light having a wavelength of 610 nm-650 nm, a green lighthaving a wavelength of 530 nm-570 nm, or a blue light having awavelength of 450 nm-490 nm. In another embodiment, the first mainwavelength can be different from the second main wavelength.

In order to avoid the first light from the active layer 332 of the firstsemiconductor structure 22 being emitted toward the second semiconductorstructure 24, the trench 20 comprises one or more insulation layer. Theinsulation layer comprises an insulation material for absorbing thefirst light or reflecting the first light. The insulation materialcomprises an organic polymer material or inorganic material.

A reflective layer 12 of the light-emitting device 300 overlayingportions of the first semiconductor structure 22 is physically connectedwith the reflective layer 12 overlaying portions of second semiconductorstructure 24. In a top view, the reflective layer 12 is configured toarrange at a position corresponding to the light-emitting area, and thereflective layer 12 has an area substantially equal to or larger thanthat of the light-emitting area. When the first light and/or the secondlight from the active layer 332 emits toward the substrate 10, the firstlight and/or the second light can be reflected toward the second-typeconductivity semiconductor layer 333 and escape outward at a side nearto the second-type conductivity semiconductor layer 333. Specifically,all the first light and/or the second light substantially emit outwardfrom a top surface 33S of the light-emitting device 300. In oneembodiment, the top surface 33S comprises a rough surface formed byetching or imprinting for improving the light extraction of thelight-emitting device 300.

As shown in FIG. 5A, the electrode area comprises a plurality ofexternal electrode structure. The plurality of external electrodestructure substantially surrounds the second semiconductor structure 24and comprises a first external electrode structure 28 and a secondexternal electrode structure 38. Each of the first external electrodestructure 28 and the second external electrode structure 38 can be abonding pad for wire bonding to an external structure (not shown), forexample, a submount, and therefore forming an electrical connectiontherebetween when driven by a current. The first external electrodestructure 28 and a second external electrode structure 38 respectivelycomprise an insulation layer 19 and a conductive layer 281. Theinsulation layer 19 is disposed between the second semiconductorstructure 24 and the conductive layer 281. A material of the conductivelayer 281 comprises metal or metal alloy. The metal comprises La, Cu,Al, Au, or Ag. The metal alloy comprises GeAu, BeAu, CrAu, AgTi, CuSn,CuZn, CuCd, Sn—Pb—Sb, Sn—Pb—Zn, NiSn, or NiCo.

As shown in FIG. 5A, there are a pair of the first external electrodestructure 28 and a pair of the second external electrode structure 38.The pair of the first external electrode structure 28 is disposed atopposite positions and facing each other and the pair of the secondexternal electrode structure 38 is disposed at opposite positions andfacing each other. In this embodiment, the first external electrodestructure 28 and the second external electrode structure 38 arealternately arranged. In other embodiment, a number and an arrangementof the first external electrode structure 28 and the second externalelectrode structure 38 can be varied but not be limited to abovedescription.

As shown in FIGS. 5A and 5B, the light-emitting device 300 comprises aplurality of extension electrode on the epitaxial structure 33.Specifically, the plurality of extension electrode comprises a firstextension electrode 221 disposed on the first semiconductor structure 22and a second extension electrode 241 disposed on the secondsemiconductor structure 24. The first extension electrode 221 or thesecond extension electrode 241 comprises a circular shape. However, anumber and a shape of the first extension electrode 221 and the secondextension electrode 241 can be designed to enhance current spreading.

As shown in FIG. 5A, the light-emitting device 300 comprises a firstconnecting electrode 223 connecting the first extension electrode 221 tothe first external structure 28, and a second connecting electrode 243connecting the second extension electrode 241 to the second externalstructure 38.

In one embodiment, the light-emitting device 300 can comprise an ohmiccontact layer at a position corresponding to the extension electrode,for example among the first extension electrode 221, the secondextension electrode 241 and the epitaxial structure 33. As shown in FIG.5B, the light-emitting device 300 comprises a first ohmic contact layer222 disposed between the first extension electrode 221 and thesecond-type conductivity semiconductor layer 333, and a second ohmiccontact layer 242 disposed between the second extension electrode 241and the second-type conductivity semiconductor layer 333. In anotherembodiment, the light-emitting device 300 can comprise an ohmic contactlayer 362 disposed between the conductive layer 281 of the firstexternal electrode structure 28 and the second-type conductivitysemiconductor layer 333, and/or between the conductive layer 281 of thesecond external electrode structure 38 and the second-type conductivitysemiconductor layer 333. The ohmic contact layers 222, 242 have theshape as substantially the same as the first and second extensionelectrodes 221, 241, respectively. By virtue of the ohmic contact layers222, 242, 362, a contact resistance between the extension electrode andthe second-type conductivity semiconductor layer 333 and a contactresistance between the conductive layer 281 and the second-typeconductivity semiconductor layer 333 can be reduced.

As shown in FIG. 5B, the light-emitting device 300 comprises a lowerelectrode 37 formed on the substrate 10. The lower electrode 37 and thefirst external electrode structure 28 (or the second external electrodestructure 38) are formed on opposite sides of the substrate 10, therebyforming the light-emitting device 300 with a vertical-type. In addition,since the first-type conductivity semiconductor layer 331 of the firstsemiconductor structure 22 and the first-type conductivity semiconductorlayer 331 of the second semiconductor structure 24 are physicallyconnected with each other, the lower electrode 37 can electricallyconnect with the first-type conductivity semiconductor layer 331 of thefirst semiconductor structure 22 and with the first-type conductivitysemiconductor layer 331 of the second semiconductor structure 24 suchthat the first semiconductor structure 22 and the second semiconductorstructure 24 can be synchronously driven when in operation. Thesubstrate 10 is a conductive substrate and comprises a semiconductormaterial or a metal material.

As shown in FIG. 5A, the first external electrode structure 28 of theelectrode area can function as a first electrode set cooperated with thelower electrode 37 for receiving a first current to form a currentpassage therebetween such that the first semiconductor structure 22 isdriven to emit the first light with a first illumination; the secondexternal electrode structure 38 different from the first electrode setcan function as a second electrode set for receiving a second current todrive the second semiconductor structure 24 to emit the second lightwith a second illumination. The first illumination and the secondillumination can be adjustable by the first current and the secondcurrent, or by a size of the first semiconductor structure 22 and thesecond semiconductor structure 24, for example, the area of the activelayer of the first semiconductor structure 22 and the active layer ofsecond semiconductor structure 24. When the area of the active layer ofthe first semiconductor structure 22 is smaller than the area of theactive layer of second semiconductor structure 24, and a value of thefirst current is equal to that of the second current (the currentdensity of the first semiconductor structure 22 is greater than that ofthe second semiconductor structure 24), the first illumination isgreater than the second illumination. When the area of the active layerof the first semiconductor structure 22 is equal to the area of theactive layer of second semiconductor structure 24 and a value of thefirst current is greater than that of the second current (the currentdensity of the first semiconductor structure 22 is greater than that ofthe second semiconductor structure 24), the first illumination isgreater than the second illumination.

The first electrode set and the second electrode set can separately andsimultaneously receive a current. As shown in FIG. 5A, when only thefirst electrode set, i.e. the first external electrode structure 28receives the first current, the first semiconductor structure 22 isdriven to emit the first light. As shown in FIG. 6, when only the secondelectrode set, i.e. the second external electrode structure 38 receivesthe second current, the second semiconductor structure 24 is driven toemit the second light. As shown in FIG. 7, when the first electrode andthe second electrode set, i.e. the first external electrode structure 28and the second external electrode structure 38 separately receive thefirst current and the second current at the same time, the firstsemiconductor structure 22 and the second semiconductor structure 24 aredriven to simultaneously emit the first light and the second light.

The foregoing description has been directed to the specific embodimentsof this invention. It will be apparent to those having ordinary skill inthe art that other alternatives and modifications can be made to thedevices in accordance with the present disclosure without departing fromthe scope or spirit of the disclosure. In view of the foregoing, it isintended that the present disclosure covers modifications and variationsof this disclosure provided they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. A light-emitting device, comprising: alight-emitting stack having a side wall and comprising an active layerwhich is configured to emit light; a first electrode formed on thelight-emitting stack and comprising an inner segment, an outer segment,and a plurality of extending segments electrically connecting the innersegment with the outer segment; and a light-absorbing layer having afirst portion surrounding the light-emitting stack in a top view andbeing configured to absorb the light toward the light-absorbing layer.2. The light-emitting device of claim 1, further comprising aninsulation layer formed between the side wall and the light-absorbinglayer.
 3. The light-emitting device of claim 1, wherein thelight-emitting stack has a top surface having a first region, and thelight-absorbing layer has a second portion covering the first region. 4.The light-emitting device of claim 3, wherein the top surface has asecond region, the outer segment is formed on the first region, and theinner segment is formed on the second region.
 5. The light-emittingdevice of claim 1, wherein the light-absorbing layer is formed on theouter segment.
 6. The light-emitting device of claim 1, furthercomprising an ohmic contact layer formed between the inner segment andthe light-emitting stack.
 7. The light-emitting device of claim 1,wherein the inner segment or the outer segment comprises a circle,rectangle, quadrangle or polygon in shape.
 8. The light-emitting deviceof claim 3, wherein an area ratio of the first region to the top surfaceis between 10% and 90%.
 9. The light-emitting device of claim 1, furthercomprising a substrate and a reflective layer formed between thesubstrate and the light-emitting stack.
 10. The light-emitting device ofclaim 4, further comprising a reflective layer, wherein the reflectivelayer has an area substantially equal to that of the second portion. 11.The light-emitting device of claim 9, further comprising a bonding layerformed between the reflective layer and the substrate.
 12. Thelight-emitting device of claim 9, further comprising a second electrodeformed on the substrate.
 13. The light-emitting device of claim 1,wherein the light is in a wavelength range from 610 nm to 650 nm. 14.The light-emitting device of claim 1, wherein the light-absorbing layercomprises Ti, Cr, Ni or a combination thereof.
 15. The light-emittingdevice of claim 1, wherein the light-absorbing layer comprises aplurality of sublayers.
 16. A light-emitting device, comprising: alight-emitting area comprising a first semiconductor structure, a secondsemiconductor structure surrounding the first semiconductor structure ina top view, and a trench formed between the first semiconductorstructure and the second semiconductor structure; and an electrode areasubstantially surrounding the light-emitting area and comprising aplurality of external electrode structures.
 17. The light-emittingdevice of claim 16, wherein one of the plurality of external electrodestructures comprises a conductive layer and an insulation layer disposedbetween the second semiconductor structure and the conductive layer. 18.The light-emitting device of claim 17, further comprising a firstextension electrode disposed on the first semiconductor structure and asecond extension electrode disposed on the second semiconductorstructure, wherein the plurality of the external structures comprises afirst bonding pad electrically connected to the first extensionelectrode, and a second bonding pad electrically connected to the secondextension electrode.
 19. The light-emitting device of claim 16, whereinboth of the first semiconductor structure and the second semiconductorstructure are configured to emit light.
 20. A light-emitting device,comprising: a light-emitting area comprising a first semiconductorstructure, a second semiconductor structure surrounding the firstsemiconductor structure and comprising an active layer and an electrode,and an insulating layer connecting the electrode and the active layer;and an electrode area substantially surrounding the light-emitting areaand comprising a plurality of external electrode structures.